Thermal decomposition kinetics of hydrolysed product of PUREX solvent

This paper studies the thermal degradation of hydrolysed products of PUREX solvent using non-isothermal thermogravimetry. The vapourisation of n-dodecane and butanol was found by analysis of off-gas using TG coupled mass spectrometry. Ramped TG of HDBP revealed the apparent decomposition onset temperature to be 535-564 K and the mass fraction of residual phosphate on TG analysis of middle phase was found to be ~20%, indicating that dibutyl phosphate has decomposed completely and conversion from organic to inorganic phosphate was successful. The average activation energy for conversion of organic to inorganic was found to be 293 kJ⋅mol⁻¹. The mass spectra reveal that there was no formation of toxic or explosive species in the off-gas. (author)